A class of wireless services intended for quick, efficient, one-to-one or one-to-many (group) communication has existed in various forms for many years. In general, these services have been half-duplex, where a user presses a “push-to-talk” (PTT) button on a phone/radio to initiate a group communication. These services have traditionally been used in applications where one person needs to communicate with a group of people, such as field service personnel or taxi drivers, generally known as group communication services.
For a secure media communication, media is encrypted using media encryption key (MEK) before being communicated to targets, and decrypted after being received at the targets using the same MEK. Each MEK includes a time-to-live value which upon its expiration the MEK may expire and be no longer valid. When a current MEK expires during an ongoing media communication session, a new MEK is obtained and used to encrypt the subsequent media. However, since the participants of the ongoing communication session may not all receive the new MEK at precisely the same time, the transition to the new MEK may cause some media packets be decrypted with a wrong MEK; thus, negatively impacting the encryption and/or decryption of the media stream.
There is a need, therefore, for mechanisms to dynamically transition from a current MEK to a new MEK during an ongoing media communication session without negatively impacting the encryption and/or decryption of the media stream or loss of media packets.